We compared the expressive syntax and vocabulary skills of 35 boys with fragile X syndrome and 27 younger typically developing boys who were at similar nonverbal mental levels. During a conversational speech sample, the boys with fragile X syndrome used shorter, less complex utterances and produced fewer different words than did the typically…

This study examined whether the variability in development in fragile X syndrome is related to FMR protein deficiency in 53 young males with various degrees of the syndrome. FMR protein expression accounted for a small but significant amount of variance in level, but not rate, of development. Findings support the hypothesized relationship but…

Seven individuals with Prader-Willi Syndrome and seven obese individuals without the syndrome were compared on their choice of either a larger quantity of food delivered after a delay or a small quantity of food delivered immediately. Individuals with Prader-Willi selected the larger food quantity whereas choices by the obese comparison group was…

Comparison of the production of repetitive speech during conversations in 30 people with either fragile X syndrome, autistic disorder, or mental retardation not caused by fragile X found repetitive speech more prevalent among those with fragile X. Results support the hypothesis that such speech dysfluency reflects the effects of physiological…

This study evaluated figure drawings of 28 persons with Williams syndrome, 28 with mixed etiologies, and 28 with Down syndrome. Human figures from participants with Williams syndrome were no more deviant than their counterparts, nor did they show "local-global" differences. Findings support a developmental, rather than deviant,…

Pediatricians' and teachers' knowledge of physical, cognitive, and behavioral features associated with three genetic syndromes were assessed and the effectiveness of information sources about these syndromes evaluated. The surveyed sample included 53 pediatricians and 69 teachers from Northern and Central California. Respondents demonstrated…

Discussion of Williams syndrome, a genetic disorder with a variety of medical and developmental features, focuses on frequent outward expression of happiness. Analysis of the unique expression of happiness in individuals with Williams syndrome is followed by discussion of this happiness in the context of other dimensions of the syndrome,…

Analysis of questionnaires completed by caregivers of 77 individuals with Cornelia de Lange syndrome in the United Kingdom found a significant association between self-injurious behaviors and self-restraint, and those displaying both behaviors displayed significantly more compulsions than did those not exhibiting them. Findings extend the…

Three models of behavioral effects of genetic disorders characterized by mental retardation were compared: (1) no-specific effect model (all genetic disorders have identical behavioral outcomes); (2) totally specific model (each genetic disorder has unique outcomes); and (3) partially specific model (two or more genetic disorders share outcomes…

The study compared the deviant, repetitive language of 33 males (9 with Down syndrome, 12 with fragile X syndrome, and 12 with autism). Results indicated that males with fragile X syndrome manifest deviant, repetitive language that is distinct from males with either Down syndrome or autism. (DB)

The study found that mentally retarded males (N=18) above 12 years of age with a fragile site on the X chromosome exhibited a highly idiosyncratic stereotypic form of gaze avoidance during greeting ceremonies. Results suggest this aberrant greeting behavior may be uniquely associated with this syndrome of mental retardation. (Author/DB)

In this study, we examined the nature, timing, and correlates of divorce in families of children with Down syndrome (647), other birth defects (10,283) and no identified disability (361,154). Divorce rates among families of children with Down syndrome were lower than in the other two groups. When divorce did occur in the Down syndrome group,…

Cognitive and behavioral effects of temporarily elevating levels of phenylalanine in treated phenylketonuria (PKU) were investigated in a triple-blind crossover study with 16 early and continuously treated children and adolescents with PKU. Results suggest that intellectual ability, memory, and conduct are not affected by medium-term elevated…

The cytogenetic survey of 67 individuals previously identified as having mental retardation and autistic behaviors revealed only 1.5 percent with the fragile X chromosome. The finding suggests that most persons with fragile X syndrome do not have autistic behaviors severe enough to be identified as a secondary psychiatric diagnosis. (Author/DB)

This nontechnical review of the literature on Rett Syndrome, a developmental disability found only in females, examines the syndrome's history, diagnostic criteria, clinical stages, incidence, differential diagnosis, etiology, genetics, treatment approaches, and prognosis. (Author/DB)